Diseases that damage the retina or optic nerve affect both pupillary and visual function. Poor vision in an eye with retinal or optive nerve disease is associated with a decrease in the pupillary response to light in that eye. Clinicians judge the pupillary response by shining a light in the eye and observing the change induced in pupillary size. More detailed analysis of pupillary responses requires pupillographic recording, just as analysis of eye movements requires eye movement recording. The application of pupillography to diagnosis of retinal and optic nerve disease has been limited. Changes in time of onset and amplitude of the pupillary constriction to light have been described, but the quantitative relationshps between these and other characteristics of the defective pupillary light reflex are not known. I plan to measure the reactions of the pupil to a variety of light stimuli under a variety of conditions, using both a television pupillometer and a photo-detector to record pupil movements. These measurements will be done in patients with several different diseases as well as in normal subjects. I will determine the relative sensitivity of these pupillary tests in detecting disease and compare these in different diseases. Certain types of optic nerve disease (e.g. optic neuritis) may have unique pupillary dynamics. I hope to show that more information about a patient's disease can be elicited from the pupil examination than is being derived with current methods for pupil testing.